The overarching goal is to characterize the physical processes in the bottom boundary of the northern South China Sea (SCS).  The proposed research is to observe, understand and quantify deep currents, bottom boundary-layer structure, and mixing in sloping bottom boundaries along a submarine banks, steep ridges, and deep-ocean depths in the northern SCS.  The specific objectives are: To quantify temporal variability of currents and mixing strengths in the water column, especially in the bottom boundary layer; To quantify internal-wave variability and their role on interior ocean mixing; To characterize the multiple time scale (tidal to seasonal) variability of the height of the bottom boundary layer and relation to mixing effectiveness. A field observational program has been planned for 2024-2026 that includes moored measurements in addition to ship-based profiling observations.